1978 FJ40 brake light issues (5 Viewers)

[Jbomb76]

Having issues with my brake lights. I have replaced the brake switch. I have traced all wires going to the hazard switch, and all the way to the taillights (No issues). I have replaced the taillights as the old ones needed to be replaced. I have replaced the flasher (just in case), and all lights are working ( turn signals, quarter rear light, low/high beams & hazards). I have searched the forum and can’t find a definitive answer as to what might be the problem. I have read the wiring schematics and see all light wires go through the hazard switch. My last option before I take it to Caveman Xchange in El Paso, Texas (Landcruiser specialist), would be to replace the switch. Any help would be much appreciate. Thanks in advance.

 

[brian]

Having issues with my brake lights. I have replaced the brake switch. I have traced all wires going to the hazard switch, and all the way to the taillights (No issues). I have replaced the taillights as the old ones needed to be replaced. I have replaced the flasher (just in case), and all lights are working ( turn signals, quarter rear light, low/high beams & hazards). I have searched the forum and can’t find a definitive answer as to what might be the problem. I have read the wiring schematics and see all light wires go through the hazard switch. My last option before I take it to Caveman Xchange in El Paso, Texas (Landcruiser specialist), would be to replace the switch. Any help would be much appreciate. Thanks in advance.

so, whats the problem?

 

[Jbomb76]

so, whats the problem?

Forgot to mention, when I press the break pedal the break light don’t turn on.

 

[Pighead]

Check the fuse?

 

[Jbomb76]

Check the fuse?

Yes, they are good.

 

[Cromagnon]

At the Stop Light Switch, do you have 12V on the GW wire from the Hazard Flasher Switch? If no, correct this before looking anywhere else. If yes, is there 12V at the GW wire coming from the Stop Light Switch when the pedal is pressed. If no, replace the Stop Light Switch. If yes, check the voltage at each Stop Light Receptacle, again with the pedal pressed. If no, correct the wiring problem. If yes, clean the receptacles and grounds. This is using the assumptions that you checked the fuses and bulbs with a multimeter and not your Mark I Eye Ball and your battery is charged.

 

[ToyotaMatt]

the Hazard Switch Circuit inside the switches can and do burn up frequently ...........

charred contacts and connector terminals melted too

 

[Jbomb76]

I have no power coming from the brake switch....switch replaced and still don’t have power...checked the hazard switch and it’s working fine.....I texted the wires coming out from the firewall to the taillights and have all lights except the break lights

 

[pb4ugo]

Do you have power going to the brake light switch?

 

[Jbomb76]

Do you have power going to the brake light switch?

I have not. Working mids and the afternoon are to hot 105. Would you please tell me how to check.

 

[pb4ugo]

At the Stop Light Switch, do you have 12V on the GW wire from the Hazard Flasher Switch? If no, correct this before looking anywhere else. If yes, is there 12V at the GW wire coming from the Stop Light Switch when the pedal is pressed. If no, replace the Stop Light Switch. If yes, check the voltage at each Stop Light Receptacle, again with the pedal pressed. If no, correct the wiring problem. If yes, clean the receptacles and grounds. This is using the assumptions that you checked the fuses and bulbs with a multimeter and not your Mark I Eye Ball and your battery is charged.

You said you checked the fuses. A common issue that arises with the fuse box is, the fuses will check out good, but the contact between the fuse and the fuse box contacts can become corroded or dirty. Sometimes when I turn on my head lights they dont work. If I slightly move the fuse back and forth in the fuse box cantact/holder they come on. You might want to remove the fuses and clean the fuse box clips 1st. Start with the simple stuff.

 

[Jbomb76]

You said you checked the fuses. A common issue that arises with the fuse box is, the fuses will check out good, but the contact between the fuse and the fuse box contacts can become corroded or dirty. Sometimes when I turn on my head lights they dont work. If I slightly move the fuse back and forth in the fuse box cantact/holder they come on. You might want to remove the fuses and clean the fuse box clips 1st. Start with the simple stuff.

I have done that and remove the fuse holder and tested the wires and they are good.

 

[BeerM3]

I have not. Working mids and the afternoon are to hot 105. Would you please tell me how to check.

Here's a nice diagram someone recreated that I saved from somewhere on this site a while ago. For a '78 it's basically the power comes straight to the STOP fuse to the stop switch. That should be an "always hot" feed so if your tester doesn't light up when touching the GW wire then check both sides of the fuse and make sure it's hot on both. But also note the GW wire where it tees off and goes to the hazard switch. If the GW is hot at the hazard but not the brake switch, then there could be a melted or broken wire where I put the yellow dot?

 

[BeerM3]

Also, have you tried unplugging the stop switch and using a small jumper wire to bypass it? That should send power to the brake lights if the circuit is working properly.

 

[Coolerman]

FYI: The Hazard switch has NOTHING to do with brake lights on a 1978 FJ40.

Fuse 2 (second from the top) is the brake light fuse. This fuse should have power at all times. On the back of the fuse panel will be a 5 position BLACK connector. going into that connector will be a Green/White wire. It is between a Green/Red and a Red/Black wire. If that wire is all melted you have found the problem. IF you find that wire melted, you will find a blown fuse.
If it looks good, use your meter and from the back test to see if that wire has power. If it does not then check the large White/Blue wire opposite the Green/White wire to see if it has power. If there is no power on the White/Blue wire, unplug the GREEN connector from the back of the fuse panel and clean the terminals sticking out. Plug the connector back in and re-test.
If you do have power on the White/Blue wire then unplug the black connector from the back of the fuse panel and clean the terminals sticking out. Plug it back in and re-test. If it still does not have power it's the fuse. I don't care if it looks good, REPLACE IT! They can fail and still look brand new!
Until you get power to the Green/White wire you will not have brake lights.

 

[tls3601]

FYI: The Hazard switch has NOTHING to do with brake lights on a 1978 FJ40.

Fuse 2 (second from the top) is the brake light fuse. This fuse should have power at all times. On the back of the fuse panel will be a 5 position BLACK connector. going into that connector will be a Green/White wire. It is between a Green/Red and a Red/Black wire. If that wire is all melted you have found the problem. IF you find that wire melted, you will find a blown fuse.
If it looks good, use your meter and from the back test to see if that wire has power. If it does not then check the large White/Blue wire opposite the Green/White wire to see if it has power. If there is no power on the White/Blue wire, unplug the GREEN connector from the back of the fuse panel and clean the terminals sticking out. Plug the connector back in and re-test.
If you do have power on the White/Blue wire then unplug the black connector from the back of the fuse panel and clean the terminals sticking out. Plug it back in and re-test. If it still does not have power it's the fuse. I don't care if it looks good, REPLACE IT! They can fail and still look brand new!
Until you get power to the Green/White wire you will not have brake lights.

I like this, they frequently look good but are bad already. Thanks for posting this Mark. A couple years back I thoroughly cleaned my fuse block, there was a load of crud in and around it. Made a huge difference in several areas.

 

[Jbomb76]

First off I would like to thank everyone for their input and assistance. I finally figured out the brake light issue (per se). When the problem initially started i bought and OEM brake switch, unfortunately the design is garbage. The reason it's garbage is because the two green wires that are sauter break off as you screw in the switch (no matter how delicate you are), and can't repair unless you break open the box. I bought my second switch from ROCKAUTO, and their design is a lot better as it has two prongs that stick out, making repairs much easier. Overlooking everyone's advise, and revisiting the issues and checking all the cables/fuses, I simply had to manually and aggressively click the break switch on/off several times before it began to work.

 

[Jbomb76]

While looking the cables over, I found these two cable which I, believe to ground cables. Can someone help me identify the two cables to the right of the picture by the wiper switch?

 

[Coolerman]

Those are NOT ground cables!!!
Those are the Amp Meter connections. White goes to the + termial White/BLue to the - terminal on the Amp Meter.

Be very careful! If you have the battery connected, let the White wire (goes directly to the battery + terminal through the fusible link) touch ground, and you don't have a working fusible link, you will at best have a fireworks show, and at worst melt your harness down... The White/Blue wire goes to the alternator B+ terminal.

 

[Jbomb76]

Thank you for the info. I tested them and don’t have any power going into them. I have a Chevy 350 in my 40, but the PO put an after market amp meter since the original one is missing.